<template>
  <div class="show-if-initialized" :class="{ initialized }">
    <pre ref="editor"></pre>
  </div>
</template>

<style lang="scss">
.show-if-initialized {
  opacity: 0;

  &.initialized {
    opacity: 1;
  }

  & > * {
    transition: none;
  }
}
</style>

<script>
import ace from 'ace-builds'
import 'ace-builds/webpack-resolver'
import jsonParse from '../utils/jsonParse'
import debounce from '../utils/debounce'

const DEFAULT_THEME = 'twilight'

export default {
  props: {
    value: {
      type: String,
      default: ''
    },
    theme: {
      type: String,
      required: false
    },
    lang: {
      type: String,
      default: 'json'
    },
    lint: {
      type: Boolean,
      default: true,
      required: false
    },
    options: {
      type: Object,
      // eslint-disable-next-line vue/require-valid-default-prop
      default: {}
    }
  },

  data () {
    return {
      initialized: false,
      editor: null,
      cacheValue: ''
    }
  },

  watch: {
    value (value) {
      if (value !== this.cacheValue) {
        this.editor.session.setValue(value, 1)
        this.cacheValue = value
        if (this.lint) this.provideLinting(value)
      }
    },
    theme () {
      this.initialized = false
      this.editor.setTheme(`ace/theme/${this.defineTheme()}`, () => {
        this.$nextTick().then(() => {
          this.initialized = true
        })
      })
    },
    lang (value) {
      this.editor.getSession().setMode('ace/mode/' + value)
    },
    options (value) {
      this.editor.setOptions(value)
    }
  },

  mounted () {
    const editor = ace.edit(this.$refs.editor, {
      mode: `ace/mode/${this.lang}`,
      ...this.options
    })

    // Set the theme and show the editor only after it's been set to prevent FOUC.
    editor.setTheme(`ace/theme/${this.defineTheme()}`, () => {
      this.$nextTick().then(() => {
        this.initialized = true
      })
    })

    if (this.value) editor.setValue(this.value, 1)

    this.editor = editor
    this.cacheValue = this.value

    editor.on('change', () => {
      const content = editor.getValue()
      this.$emit('input', content)
      this.cacheValue = content
      if (this.lint) this.provideLinting(content)
    })

    // Disable linting, if lint prop is false
    if (this.lint) this.provideLinting(this.value)
  },

  methods: {
    defineTheme () {
      if (this.theme) {
        return this.theme
      }
      return DEFAULT_THEME
    },

    provideLinting: debounce(function (code) {
      if (this.lang === 'json') {
        try {
          jsonParse(code)
          this.editor.session.setAnnotations([])
        } catch (e) {
          const pos = this.editor.session.getDocument().indexToPosition(e.start, 0)
          this.editor.session.setAnnotations([
            {
              row: pos.row,
              column: pos.column,
              text: e.message,
              type: 'error'
            }
          ])
        }
      }
    }, 2000)
  },

  destroyed () {
    this.editor.destroy()
  }
}
</script>
